Chokeless carburetor



July 17, 1962 J. o. sARTo 3,044,751

cHoKELEss CARBURETOR Filed July 15, 1959 2 Sheets-Sheet 1 l, a, Ilm

IN V EN TOR.

dDH/vw O. .SHR To #W Hm /rrra RNE/s' July 17, 1962 J. o. sARTo 3,044,751

CHOKELESS CARBURETOR l Filed July 15, 1959 2 Sheets-Sheet 2 /zf 7 z :4 JNVENToR 1 /f/ i4 j c/oRM/l O. @SHRTO /77 Taf/szw;

United States Patent 3,@44,751 Patented July 17, 1962 ice This' invention relates to improvements ina carburetor forthe internal combustion engine of an automotive vehicle and has for an important object the provision of improved means for supplying enrichment fuel to the engine during starting and running under cold engine conditions.

Another object is to provide an improved carburetor which eliminates thecustornary choke valve and thereby enables reduction in the height yof the usual downdraft air horn andachieves a low silhouette carburetor as required by modern automobile styling.

Another object is to provide an enrichment fuel supply opening through an enrichmentport into the customary air inlet induction conduit at a location downstreamof the throttle valve, thereby to` avoid icing of the throttle valveparts of the induction conduit system, the chamber beingl in communication with each of the parts and containing a valve actuating member.v The enrichment port is controlled by adjustable enrichmentfvalve means having a stem projecting through the port into the chamber and being movable in the direction into the chamber to cause the valve means to restrict the port, and being mov-able in lthe opposite direction to cause the valve lmeans to decrease the restriction of the port. Temperature sensing means responsive toA engine temperature is cooperable with the actuating member for adjusting the valve means to decrease the enrichment fuel ow through said port with increasing temperature by effecting engagement between the actuating member and stem.

Among other advantages resulting from the above arrangement, a single enrichment valve means can be feasibly employed for use with both-barrels of a two-barrel carburetor for example. The enrichment fuel will be supplied alternately and in substantially uniform quantities to the two barrels in consequence of the customary alternate firing of engine cylinders associated' with the two barrels respectively. Also by virtue of the stem ofthe valve means projecting through the enrichment port and being engageable by the actuating member within the aforesaid chamber, sealing ofthe valve means is facilitated and a simple, economical, and particularly efficient structure is achieved.

Another object is to provide a structure of the above character-wherein the enrichmentvalve means has'cold starting and cold iunningpositions and wherein means responsive to` operation of the engine, as for example, means responsive to pressure changes in the induction conduit, are provided to cooperate with the actuating memberl to augment the effect ofthertemperaturesensing means inlrestricting the enrichment fuel ow with increasing temperature when the engine is running.

Another object is to provide such a device wherein the means responsive to operation ofthe engine has a cold starting position cooperable with the tempera-ture sensing means throughout a predetermined cold' temperature range for adjusting the enrichment valve means to a cold starting position during starting of the engine and: for adjusting the enrichmentA valve means to a cold running position when the engine is running in said temperature range atidlerto moderate load.

Still other objects are to provide such a construction having a fast idle cam cooperable with the temperature` sensing means and the aforesaidmeans responsive tol operation of the engine and also with ythe throttle operating linkage for progressively decreasing the minimum throttle opening at idleispeeds with increasing temperature during a predetermined cold temperature range; andl wherein an unloader mechanism cooperable with the throttlelinkage and'with the actuating member is provided to adjust the enrichment valve means to `a position for closing the enrichment port when the throttle valve is moved to a wide open position.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this speciiication wherein like reference characters designate corresponding parts in the several views.

FIGURE l is a fragmentary schematic mid-sectionalI view of a carburetor structurev embodying the present invention, poitions being broken away to show details of construction.

FIGURE 2 is a fragmentary bottom sectional view taken in the direction of the arrows substantially along the line 2--2 of FIGURE 1 and showingthe cold enrichment valve in the cold starting position.

FIGURE 3 is a fragmentary view similar to FIGURE 2L showing the coldenrichment valve in the cold running position.

FXGURE 4 is a View similar to FIGURE 2, but showingthe cold enrichment valve in the hot position.

FIGURE 5 is a fragmentary side elevational view of the lower portion of the carburetor illustrated in FIGURE l.

FIGURE 6 is a View similar to FIGURE 5;v but with portions of the throttle linkage removed to show details of construction.

FIGURE 7 is a fragmentary bottom view of FIG- URE 5.

FIGURE 8 is a fragmentary verticalV sectional View' showing the vacuum actuated piston and temperature sensing mechanism, taken in the direction of the arrows piston at its limit of leftward movement.

lt is'to be understood that the invention is not'limit'ed in its application to the detaiis of construction and yarrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practicedor carried out in various ways. Also it is to be understood that the phraseology or terminologyl employed herein is for the purpose of description and not of limitation.

Referring tothe drawings, a carburetor embodying the system. VThe castings 10 and 11 are suitably separated iby a gasket 13 and thev castings 10 andlZ are separated by a suitable gasket `1,4. The upper air horn casting 1'1 is provided with an exterior flange 1,5 adapted forattachment with the usual air filter and is also providedwith a vertical induction conduit 16' which supplies air to the engine by conventional downdraft action;

'In accordance with usual construction, the air induction conduit 16 is providedwith a butter-ily type choke valve. below, no, such choke valve is required, so that the vertical dimension of, the air horn casting 11 is appreciably reduced and a particularly low silhouettev carburetor de'- By virtue of the present invention as described t sign is rendered feasible in accordance with the demands of modern automobile styling. Within the body 10, the induction conduit 16 bifurcates into two parallel conduits, each being formed to provide a venturi 17 having its throat within the body portion and discharging downwardly into one of each `of a pair of parallel conduit parts 18 in the throttle body 12. The induction conduits 18 conduct a fuel-air mixture to the engine cylinders in the usual manner.

The body casting 10 is also formed with an integral fuel bowl 19, whereas the air horn casting 11 is formed with an integral fuel kbowl cover 29, the bowl 19 and cover 20 being spaced by the gasket 13. A tubular coupling 21 having an externally threaded extension 22 is screwed tightly into the left end of the fuel bowl 19. The bore 23 of the extension 22 carries an axially slidably ribbed valve shaft 24 having a conical valve element 25 at its left end seating at the mouth of a restricted port 26 opening into the bore 23. The shaft 24 may be of conventional construction and comprises three or four longitudinally extending ribs at right angles to each other to enable fuel flow passages longitudinally of the bore 23 in the spaces between the ribs. The left or upstream side of port 26 in FIGURE l opens into an enlarged bore 27 through an externally threaded inlet fitting 28 adapted to be connected with the usual fuel pump which supplies pressurized fuel to the interior of the bowl 19 via port 26 and bore 23. The fuel level Within the bowl 19 is maintained by a pair of oats 29 at opposite sides of the carburetor vertical mid-plane and connected by bracket arms 30 to a vertical hinged bracket 31 pivotally mounted at 32 within the fuel bowl 19.

As the fuel within bowl 19 attains a predetermined desired level, upward movement of the floats 29 ur-ges bracket 31 counterclockwise about its pivot 32 into er1- gagement with the right end of valve shaft 24, thereby urging the conical valve portion 25 into seated position at port 26 to close the latter to inlet fuel. When the fuel level within bowl 19 drops below the predetermined desired level during operation of the engine, the floats 29 likewise swing downwardly, causing bracket 31 to swing clockwise away from the'right end of shaft 24, whereby the inlet fuel pressure from the vehicle fuel pump urges valve 25 from its closed or seated position at port 26 to refill the bowl 19 to the aforesaid desired level.

Separating the induction conduit 16 and fuel bowl 19 is a vertical wall 33 having a platform 34 formed therein at the induction conduit side of the wall. A venturi cluster 35 has a portion seated on the platform 34 and supports a pair of integral small venturis 36, one discharging coaxially into one of each of the venturis 17 adjacent the throat of the latter. Each small venturi 36 is provided with a main fuel supply nozzle 37 which is suitably connected in accordance with customary practice with the fuel supply in the bowl 19 and discharges into the venturi 36 adjacent the latters throat. A hollow clamping screw 38 which may comprise part of the idle air vent system secures the venturi cluster 35 to the platform 34. A portion of the acceleration fuel duct system illustrated at 39 communicates at one end via check valve 46 with an acceleration discharge orifice which opens into induction conduit 16 from the venturi cluster 35 and is connected at its other end with the usual throttle actuated acceleration pump not shown. The acceleration duct system 39 is vented by vent duct 49 in communication with vent tube 41 which opens within the upper portion of the conduit 16. A bowl vent 42 also in communication with vent tube 41 is suitably connected with the upper portion of fuel bowl 19. A pair of throttle valves 43 are mounted in the upper portions of the two induction conduit parts 18 respectively on a common horizontal pivotal shaft 44 which in turn is mounted in the throttle body.

The structure and operation of the fuel supply system described thus far may be conventional if desired and are accordingly not disccussed in further detail herein. If

desired, reference may be had to the copending application of applicants assignee, Serial No. 818,971, tiled June 8, 1959, for a more detailed description of the above structure.

Referring to FIGURES 5 and 6, a throttle link 45 is keyed to and rotatable with one end of the throttle shaft 44 which extends transversely beyond the throttle body 12. Pivotal freely on the throttle shaft 44 adjacent and inwardly of the link 45 is a cam follower 47 which carries an adjusting screw 43. The inner end of the screw 43 is adapted to engage the various surfaces of a fast idle cam 49 pivoted on horizontal shaft 50 mounted on body casting 10. In the present instance, cam 49 is provided with three segmental surface portions 51a, 51b, and 51e of decreasing radius concentric with the axis of shaft 50. It is apparent that upon counterclockwise pivoting of cam 49 from the position shown in FIGURES 5 and 6, cam follower screw 48 will ride successively along the surfaces Sla, 51b, and 51C and thence finally out of engagement with cam 49. By suitably adjusting screw 48, the angular position of follower 47 can be predetermined for any angular position of cam 49.

As illustrated in FIGURE 5, throttle link is provided with an inturned abutment 52 adapted to underlie cam follower 47, whereby the extent of counterclockwise pivoting of link 45 and correspondingly the extent of closure of throttle valve 43 is limited in accordance with the position of cam 49 and the adjustment of screw 48.

A slow idle adjustment 53 screws through a boss 54 of the throttle body 12 and is adjustably positioned to engage the throttle abutment 52, thereby to provide means for limiting the maximum closure of throttle valve 43 when cam 49 pivotsV counterclockwise out of engagement with screw 48. Spring 55 under tension between boss 54 and the head of screw 53 maintains the latter in its adjusted position.

A connecting link 56 is pivotally connected at its upper end 57 to an extension of cam 49 directed substantially oppositely from the cam surface 51a and at its lower end 58 to the upper extension of a dog-leg .link 59 freely pivotally adjacent its knee on a lateral exten sion of a pivotal shaft 60 which extends through the throttle body 12 in parallelism with shaft 44. A crank arm 61 keyed on shaft 60 to rotate therewith is provided with an extension overlying an outturned abutment 62. The latter is integral with the lower extension of link 59 and underlies crank arm 61 so as to swing link 59 counterclockwise upon counterclockwise pivoting of arm 61, and to free link 59 for clockwise pivoting upon clockwise swinging of arm 61. In the arrangement shown, the linkage including dog-leg link 59, link 56, and cam 49 are unbalanced so as to exert a gravity induced force urging clockwise pivoting of link 59. Thus when the frictional engagement between the inner end of screw 48 and cam 49 is relaxed, as upon clockwise pivoting of throttle link 45 to open throttle valve 43, abutment 62 of link 59 will be urged by gravity force upwardly or in a clockwise direction against the underside of crank arm 61. The customary idle enrichment screw 63 and a fragmentary portion of the usual accelerator pump link 64 pivotally connected at 65 to the throttle link 45 for actuation thereby are also illustrated in FIGURES 5 and 6.

Referring again to FIGURES l and 2, a radially extending bracket 66 is suitably keyed to a central portion of the actuating shaft 60 to pivot therewith. An arcuate cam 67 having a leg 68 parallel to bracket 66 is adjustably secured to the latter by screws 69 so as to engage the tip of a valve stem 70. The latter extends through a metering orice 71 in an end plate of an externally threaded tubular housing or nut 72 which is provided with a ange enlargement 73 overlying juxtaposed portions of the throttle body 12 and suitably spaced therefrom by a sealing washer 74.

In the usual carburetor construction, the space between the throttle body induction conduits 1S is filled solidly With the material of the throttle body casting. In the present instance, a chamber 75 is formed in the lower portion of the throttle body casting between the induction conduit parts 18 so as to connnunicate with these parts and with port 71 and to provide space for swinging movement of cam 67. The externally threaded portion of valve housing 72l screws into a portion of reduced diameter of a cylindrical chamber 80 in throttle body 12. The right end of the tubular portion of'housing 72 in FIGURES 2-4 is tightly sleeved over a reduced diameter tip 76 of a tubular outer housing 77 having substantially the same diameter as the tubular threaded portion of housing 72. The outer or right end of housing portion 7.7 contains a screw plug 78` having a fuel metering orice 79 connecting the interior of housing portion 77 and chamber 80. The outer end of chamber 80 is suitably closed by a closure plug 81.

Fuel is supplied to the chamber titi via inlet port 82 in communication with a fuel enrichment conduit 83 formed in the throttle body 12, FIGURE l. The latter conduit is a continuation of conduits 84 and 85 in the carburetor body casting l andcoupling 21l respectively. As illustrated in FIGURE l, conduit 85 communicates with the fuel inlet conduit 27 upstream of metering orifice 26 so as to receive. pressurized fuel directly from the engine fuel pump. The advantage of this structure is that the enrichment fuel is supplied under the fuel pump pressure to chamber Si). However it will be apparent from the following that the conduits 83, S4 could receive the enrichment fuel supply directly from the fuel bowl 19, rather than from conduit S5 and the inlet conduit 2,7 as shown. Inner and outer sealing rings S6 and S7 are provided concentrically around the axis of couplingZlf to provide a suitable seal between the latter and fuel bowl 19 around both the threaded extension 22 and the conduit 85.

Fuel from chamber Sil is admitted to the interior of tubular housing portion 72 via metering port 89. Discharge of fuel from the interior of housing 72 through port 71 is controlled by a cold run tapered valve 99 at the right endV of stem 69. Also extending rightward from valve 90 is an integral coaxial stem 91 having a conical spring therearound under compression between a radially inward projection of tip 76 and the base of tapered valve 99 so as to urge the latter yieldingly to thev left in FIGURES, 2-4. Stem 91 also extends rightward through a cold start orifice 9.3 formed centrally in tip 7u, which orice is normally closed by meansof a conically taperedvalve 9d when the engine is running. Valve 94 has an inwardly opening socket for slidably receiving the outer endY of stem 9:1 andis provided with an outwardly or rightwardly extending` stem 95 having a conical spring 96 therearound under compression between plug 7S and the, base of valve 94 to urge the latter yieldingly leftward to cl'ose orificef.

In accordance with the foregoing structure, fuel from the customary engine fuel pump is supplied from inlet conduit 27 to conduits S5, En, and S3 and port Sitinto cham,- ber From chamber-gfuel enters the interior of houing 72- via port 89 and. the interior of housing 77 via port 79. Arcuate cam 67 isforme'd'with a progressivelyI decreasing radius in the direction of its extension from leg 6b, so that when actuating shaft 69 and cam 67 pivot counterclockwise to their limit of movement illustrated in FIGURE l, stem 7tlwill be forced rightward against the tension of springs 92 and' 96 to open both ports 93 and 71, FIGURE 2. rIhe position of FIGURES ll and 2 is known as the coldstarting position whereat the enrichment valve means 9i?, 94 supplies maximum enrichment fuel under the pressure of the fuel pump to chamber 75V from which fuel isy drawn alternately into the twofinduction conduits. IS-.as required inaccordanceV with the customary alternate suction strokes ofthe engine.

pistons associated with 'the conduits 18.

Upon clockwise pivoting of camA 67 in 'FIGURE l,l

stem 70 is enabled to move progressively leftward until the cold running position of FIGURE 3 is attained whereat valve 94 closes orifice 93, but orifice 711 isstill, substantially open.' At this position as described more;

which latter is only partially restricted by the leftw-ard' position of valve Upon continued clock-wise swinging; of cam 67, stern 7i) is allowed to move to the-limit ofits` leftward movement to the hot running position of'FIG- URE 4 whereat both orifices 71 and 93 lare closed by their respective valves 90 and 94.

In the event of flooding of the engine, as for example. by excessive pumping of the acceleration fuelpump dur-- ing starting under warm or hot conditions, an unloader arm 97 is provided integrally with the throttlev link 45,

FIGURES 5 and 6. Arm97 is disposed'to engage an unloader projection 9S on the fast idle cam 49 and swingthe latter to the limit of its countercloclcwise movement when the throttle link 45 is moved to its limit of clockwise movement'whereat the throttle valve iiisfully open. In consequence of the counterclockwise pivoting of cam 49, link. 56 will swing dog-leg lever 59 clockwise and cause abut-- ment 62 to engage crank arm 61, thereby to swing the vlatter and cam 67 clockwise tothe lowermost dotted position; illustrated in FIGURE 5*. At this position-both por-ts 7'1` and 93 will be closed as in FIGURE 45o as `to cutoff enrichment fuel.

In order to render the angular position of shaft (S0-re-- sponsive to engine temperature, a yoke-typebracket 99^is keyed to a lateral extension of shaft 65 by reason of a flatltltl formed thereon, FIGURE 8. The bracket 9911's provided with yoke arms 101 spaced by shaft 6u and extending in one radial direction therefrom. The outer ends of the yoke arms 101 are drawn tightly together by a screw 102 and nut 103 to clamp the brackety 99securely to shaft 60. Bracket 99 is also-providedfwitha radial extension directed substantially oppositely from theV yoke arms 16d and pivotally connected at 104 to the upper end of a connecting link 105'. The lower end of link 105 extends into the free cupped end 106 of a coiled bimetallic spring 107 illustrated schematically in FIGURE 8 and having aninner end 108 suitably secured Vto a fixed portionr of the engine. The bimetallic spring 107 is responsive to engine temperature such. that with decreasing temperature. it tends kto urge link 165 upwardly and pivot shaft 6i? clock- Wise in FIGURE 8. Inasmuch as FIGURE 8 shows an end view of shaft 60 at the opposite side of the carburetor from FIGURE 5, clockwise pivoting in FIGURE 8 is the same as counterclockwise pivoting in FIGURES. Thus with decreasing temperature, cam 67 is urged in a counterclockwise direction toward the raised cold starting position of FIGURE l. With increasing temperature, spring 1017 enables downward movement of shaft 105 and downward or clockwise swinging of cam 67 in FIGURE l.

In order that the angular position of shaft 60 will also be responsive to changes in engine condition from starting to running, a bracket 109 is also secured on the flat 100 of shaft 60 and to the base of a yoke 110 extending radially from shaft 611, FIGURES 7 and 8. The outer ends of the arms of the yoke 11dy are pivotally connected by pin'111 to one end of a piston rod 1112 having` itsother endpivotally secured at 113 to a piston 114 reciprocable within a cylindrical housing 1115 mountedin throttlel body 12. The outer endof cylinder 115 is closed by a suitable closure 116. The inner end of cylinder 115 opens to the atv mosphere at port 117 through 'whichy piston rod 112 extends.

An annular recess 1'1'8formed in the outer periphery of,y piston 114 communicates by'means of a plurality of radial ducts 119 with an interior bore 120 which is formed in piston 114 and opens at the inner or right end of the latter into cylinder 11S, FIGURE 8. Thus the interior bore 12@ communicates through the inner portion of cylinder 11S and port 1117 to the atmosphere. Extending from the eft end of cylinder 115 in its inner surface for slightly greater than half the length of the latter is a groove 121 which opens at its leftward or outer end in FIGURE 8 at a port 122 in communication with a low pressure duct 123. The latter extends within the body of cylinder 115 and communicates with duct 124 which extends the throttle body 12 and opens into one of the induction conduits 1t downstream of throttle valve 43, thereby to connect groove 121 with the low pressure existing in the inductio conduit when the engine is running.

In order to facilitate description of the operation of the structure described thus far, in FIGURE 8 the leading or outer edge of the annular groove 118 is designated by the letter A, the `trailing or inner edge of piston 114 is desig nated by the letter B, the surface defining the rightward end of groove 121 is designated by the letter C, and the right end of cylinder 115 which approximately defines the limit of rightward movement of piston 114 is designated by the letter D.

vIt will be apparent that during starting of the engine, and while the latter is not running, no appreciable force will be exerted on piston 114 effecting the angular adjustment of bracket 99 and shaft 60. When the engine is running, the low pressure at the downstream side of throttle valve 43 will be conducted via conduits 124, 1.23 and port 122 to groove 121 and thereby to the left end of piston 114, urging the latter leftward. In this regard, the piston 114 substantially fills the cylinder 115 so as to minimize leakage of air between the piston and cylinder, except when the piston is moved leftward sufficiently to establish communication between grooves 118 and 121.

When the engine is not running and is in a cold condition, the thermostat spring 107 will be under tension urging shaft 105 upward and thereby urging cam 67 to the cold starting position of FIGURE 1. Although the actual temperatures for which fuel enrichment is desired will vary appreciably depending upon the type of engine and carburetor employed, an example of a temperature range requiring cold starting fuel enrichment could be any temperature below 75 F. Below this cold starting v temperature condition, the clockwise positioning of shaft 60 will not only maintain cam 67 at the position of FIGURES l and 2, but crank arm 61 abutting boss 62 will swing lever 59 to the cold starting position illustrated in FIGURE 6 whereat cam follower screw 48 rides on fast idle cam surface 51a. Also during the cold starting condition, the vacuum operated-piston 113 will be adjacent its rightward limit of movement whereat edge B is adjacent edge D.

As the engine temperature progressively rises above the cold starting condition, the relaxation of tension in spring 107 enables downward movement of shaft 105 and clockwise downward movement of cam 67 until at approximately 100 F. by way of example, the cold enrichment valve actuated by stern 70 moves to the position of FIG- URE 3 whereat port 93 is closed and port 71 is open. Simultaneously piston 114 will move approximately to the position whereat surface A is adjacent surface C in FIG- URE 8. In addition, the gravity induced force on fast idle cam 49 will swing the latter counterclockwise until surface 51a rides out of engagement with screw 48, which then rides on surface 51b.

Upon continued rise in temperature to an intermediate warm condition, say for example 115 F., fast idle cam 49 will swing counterclockwise until surface 51h rides out of engagement with screw 48, which then rides on surface 51o. During this interval, piston 114 will move leftward until surface B is adjacent surface C and cam 67 will release the cold enrichment valve to the position of FIGURE 4 whereat both orifices 71 and 93 are closed.

Thereafter upon continued rising temperature, piston 114 will gradually move leftward to the limit of its movement at approximately 150 F. and fast idle cam 49 will pivot counterclockwise until at approximately 140 F. cam surface 51e will ride out of engagement with screw 48.

The foregoing operation occurs during cranking or startingA of the engine. After the engine has started, the operation of bimetallic spring 107 yieldingly urging shaft 60 in a clockwise direction, FIGURE 8, is opposed by the vacuum actuated piston 114 urging counterclockwise movement of bracket 99 and shaft 60. Accordingly for every predetermined position of the cams 49 and 67 associated with any temperature when the engine is not running or during cranking, a second more counterclockwise position of cam 49 in FIGURE 5 and a second more clockwise position of cam 67 in FIGURE 1 will be determined when the engine is running. Thus if both orifices 71 and 93 are open at temperatures up to 75 F. during cold starting of the engine, the upper limiting temperature at which both orifices will be open will be appreciably colder after the engine has been started. For example at cold operating temperatures below 40 F., as soon as the engine starts, the vacuum induced force at the left end of piston 114 will move the latter immediately to the position whereat surface A is adjacent and leftward of surface C so as to establish communication between grooves 118 and 121. As long as the engine temperature remains at the cold running position, piston 114 will remain with the grooves 118, 121 in communication whereby suicient air will be drawn through ports 119 to prevent further leftward movement of piston 114. At this position of piston 114, bracket 99 and shaft 60 will have been swung counterclockwise sufficiently to lower cam 67 clockwise in FIGURE l so as to cause the fuel enrichment valve to shift to the position of FIGURE 3. 'Ihus the cold starting port 93 will be closed to cut off the cold starting enrichment fuel which is no longer required after the engine has started and the cold running port 71 will still be open to supply enrichment fuel during the cold running condition. At the cold running position, the fast idle cam 49 will have pivoted counterclockwise sufficiently so that screw 48 will ride on surface 51b. As the engine temperature gradually rises, the tension in spring 107 will progressively relax to enable continued counterclockwise pivoting of cam 49 until at a predetermined intermediate temperature, depending upon the type of engine and carburetor employed and the operating conditions desired, surface 51b will ride off of screw 48, as for example at approximately 55 F.

While the engine is running, the fuel enrichment valve will assume an intermediate warm running condition upon a continued rise in engine temperature to for example approximately 7 5 F. At this temperature condition, the tension in bimetallic spring 107 will have relaxed sulciently to enable the vacuum force acting on piston 114 to move the latter leftward until surface B is adjacent and leftward of surface C. At this position additional bypass for the atmospheric air flow into groove 121 and conduit 123 is provided so that piston 114 will remain substantially without further movement during continued limited increase in engine temperature.

`Finally after the engine temperature rises still higher to approximately 85 F. for example, piston 114 will begin to move leftward with increasing temperature and will reach the limit of its leftward movement at approximately 125 F. for example. Also at approximately the temperature at which the surface B moves leftward from surface C, the fast idle cam 49 will swing counterclockwise until cam surface 51C rides out of Contact with screw 48. During normal constant speed operation of the engine up to as high as 60 to 70 m.p.h. for an 8-cylinder engine, the vacuum force acting on piston 114 will be appreciable to cause operation of the latter as above described, although it will be apparent that there will be a gradually though nominal decrease in the vacuum force 9? acting on the piston 114 as the engine speed progressively increases.

Having thus described my invention, I-claim:

l. .In an internal combustion engine, a chokeless carburetor having an air inlet induction conduit, a throttle valve in said induction conduit, means for supplying engine operating fuel to said induction conduit, means for supplying Aenrichment fuel to said induction conduit during cold engine conditions including an enrichment port in communication with said induction conduit, fuel enrichment valve means for said port and being adjustable to control the enrichment fuel liow therethrough to said conduit, said valve means including a stem projecting through said port in the direction toward the induction conduit side of said port and being movable in said direction to cause said valve means to restrict said port, said stem being movable in the opposite direction to cause said valve meansto decrease the restriction at said port, actuating means having aportion engageable with said stem at theinduction conduit side of said port to adjust said valve means,.temperature sensing means responsive to engine temperature and cooperable with said actuating means to adjust said valve means to decrease the ow of said enrichment fuel through said port with increasing temperature.

2. The combination as in claim 1 wherein said valve means is adjustable to cold starting and cold running positions, and including means responsive to engine operation cooperable with said actuating and temperature responsive means to adjust said valve means to its cold starting and coldrunning positions during starting and running of said enginerespectively underV predetermined cold engine conditions.

3. In an internal combustion engine, a chokeless carburetor having air inlet induction conduit means, a pair ofthrottle valves in separate parallel parts of said conduit means, Imeans for supplying engine operating fuel to said parallel parts, means for supplying enrichment fuel to said conduit means during cold engine conditions including an enrichment port arranged between said parallelparts and opening into a chamber in communication with each of said parallel parts, fuel enrichment valve means for said port andbeing adjustable to control the flow of enrichment fuel, therethrough into said chamber, said valve means including a stem projecting through said port into said chamber and being movable in the direction into said chamber to cause said valve means to restrict said port, said stembeingmovable in the opposite direction to cause said valvermeans to decrease the restriction at said port, actuating means having a portion in said chamber engageable with` said stem for adjusting the latter inthe aforementioned directions, temperature sensing means responsive to engine temperature and cooperable-with said actuating means to adjust said valve means to decrease said enrichment fuel flow through said port with increasing temperature.

4. The combination as in claim 3 wherein said valve means is adjustable to cold startingl and cold running positions, andincludingmeans responsive to engine operation cooperable with said actuating and temperature responsive meansl to adjust said valve means to its cold starting and coldrunning positions during starting and running of said4 engine respectively, under predetermined cold engine conditions.

5'. In an internal combustion engine, a carburetor having an air inlet induction conduit, a throttle valve in said conduit, a fuel bowl associated with said carburetor, means connecting said fuel bowl and conduit forl supplying the latter` withengine'operating fuel, a fuel pump, a fuel inlet conduit connecting said pump and bowl, valve means controllingk the fuelv flow to said bowl through said inlet conduit, ducti means connected With saidV inlet conduit at a location upstream of said valve means and opening into saidinduction conduit to supplypressurized enrichment fuel-thereto, adjustable'valve meansin said-duct means for controlling the fuel flow therethrough to said induction conduit, and means responsive to engine operating temperature for adjusting the last-named valve means.

6. In an internal combustion engine, a carburetor having an air inlet induction conduit, a throttle valve in said conduit, afuel bowl associated with said carburetor, means connecting said fuel bowl and conduit forV supplying the latter with enginel operating fuel, a -fuel pump, a fuel inlet conduit connecting said pump and bowl, valve means controlling the fuel flow to said bowl through said inlet con duit, duct means connected-with said inlet conduit at a location upstream of said valve means and opening into said induction conduit to supply pressurized enrichment fuel thereto, adjustable valve means in said duct means for controlling the fuel flow therethrough to said induction conduit, shiftable actuating means for adjusting said adjustable valve means, and means responsive to predetermined engine operating conditions for shifting said actuating means.

7. In an internal combustion engine, a carburetor having an air inlet induction conduit, a throttlevalve in said conduit, means for supplying engine operating fuel to said conduit, duct means opening into said' conduit for supplying enrichment fuel thereto, adjustable valve means in said duct means for controlling the fuel flow therethrough to said induction conduit, shiftable actuating means for adjusting said adjustable valve means, means responsive to predetermined engine operating conditions for shifting said actuating means, and an unloader linkage operatively connecting said throttle valve and actuating means to shift the latter to adjust said adjustable valve means to close said duct means upon movement of the throttle valve to adjacent its wide open position.

8. In a carburetor for an internal combustion. engine having an air inlet induction conduit, means for supp-lying engine operating fuel to said conduit, a fuel enrichment duct `opening into said conduit and adapted to be connected with a source of fuel for supplying said conduit with enrichment fuel, adjustable valve means in said duct for controlling theenri'chment fuel flow therein to said induction conduit, a shiftable actuator for adjusting said, `adjustable valve means, temperature sensing means responsive to engine operating temperature and operatively connected withsaidactuator to urge said adjustable valve means yieldingly to an open position when the enginetemperature is `less than a predetermined minimum, said temperature sensing means being effective to yield progressively with increasing temperature to enable progressive opening of said adjustable valve means, and means responsive to the pressure in said induction conduit and operably connected with said actuator to enable maximum enrichment fuel flow in said duct during engine starting and to yieldingly decrease enrichment -fuel iiowin said duct in opposition to the effect of said temperature sensing means when said engine is: running.

9. The combination as in claim 8 wherein said adjustable valve means has a number of positions for incrementally decreasing lthel enrichment` fuell ilowf with in-4 creasing temperature, and wherein said means responsive to engine operation has a number of positions corresponding approximately to the first number of positions*y mum enrichment fuel to said induction conduit during,

starting of said engine and having a cold running positionl for supplying a lesser; quantity of enrichment fuel to said.

induction conduit, and wherein said means responsive to engine operation includes a pressure actuated device 0peratively connected with said induction conduit downstream of said tnrottlevalve,v said device having astarting position and a running positionand being cooperable 1 1 with said actuator and temperature sensing means to adjust said adjustable Valve means to its cold starting and cold running positions during starting and running of said engine respectively under predetermined cold conditions.

1l. In an internal combustion engine, means for supplying operating fuel to said engine, duct means for supplying enrichment fuel to said engine, adjustable valve means associated with said duct means for controlling the enrichment fuel flow therein to said engine, temperature sensing means responsive to engine temperature and operatively connected with said adjustable valve means to urge adjustment of the latter yieldingly to decrease the enrichment fuel flow in said duct means progressively with increasing temperature within a predetermined cold temperature range, and means responsive to operation of said engine and operatively connected with said adjustable valve means to augment said temperature sensing means in decreasing said enrichment fuel when said engine is running.

12. In an internal combustion engine, means for supplying operating fuel to said engine, duct means for supplying enrichment fuel to said engine, adjustable valve means associated with said duct means for -controlling the enrichment fuel ilow therein to said engine, temperature sensing means responsive to engine temperature and operatively connected with said adjustable valve means to urge adjustment of the latter yieldingly to decrease the enrichment fuel ow in said duct means progressively with increasing temperature within `a predetermined cold temperature range, and means responsive to operation of said engine and operatively connected with said adjustable valve means to augment said temperature sensing means in decreasing said enrichment fuel when said engine is running, said means responsive to operation of said engine having a starting position and a running position and being cooperable with said temperature sensing and adjustable valve means to adjust the latter to a starting position and to a running position during starting and running of said engine at predetermined cold engine operating conditions.

13. In an internal combustion engine, a chokeless carburetor having an air inlet induction conduit, a throttle valve in said induction conduit, means for supplying engine operating fuel to said induction conduit, means for supplying enrichment fuel to said induction conduit during cold engine conditions including an enrichment port in communication with said induction conduit, fuel enrichment valve means for said port and being adjustable to control the enrichment fuel flow therethrough to said conduit, a fast idle cam, cam follower means for said cam, a throttle linkage connected with said throttle valve for controlling the latter and being engageable with said follower means to limit the extent of closing of said throttle valve depending on the relative positions of said cam and follower means, actuating means cooperable with said cam for positioning the latter and also cooperable with said enrichment valve means to adjust the latter', temperature sensing means responsive to engine temperature cooperable with said actuating means to position said cam and to adjust said enrichment valve means to decrease the minimum throttle opening and the ilow of enrichment fuel through said enrichment port with increasing temperature.

14. In an internal combustion engine, a chokeless carburetor having an air inlet induction conduit, a throttle valve in said induction conduit, means for supplying engine operating fuel to said induction conduit, means for supplying enrichment fuel to said induction conduit during cold engine conditions including an enrichment port in communication with said induction conduit, fuel enrichment valve means for said port and -being adjustable to control the enrichment fuel flow therethrough to said conduit, a fast idle cam, cam follower means for Said cam, a throttle linkage connected with said throttle valve for controlling the latter and being engageable with said follower means to limit the extent of closing of said throttle valve depending on the relative positions of said cam and follower means, actuating means cooperable with said cam for positioning the latter and also cooperable with said enrichment valve means to adjust the latter, temperature sensing means responsive to engine temperature cooperable with said actuating means to position said cam and to adjust said enrichment valve means to decrease the minimum throttle opening and the flow of enrichment fuel through said enrichment port with increasing temperature, said throttle linkage including an unloader lever engageable with said cam to position the latter at an unloader position upon shifting of said throttle linkage to a wide open throttle position, said cam being cooperable with said actuating means to close said enrichment valve means when said cam is at said unloader position.

15. In an internal combustion engine, a chokeless carburetor having an air inlet induction conduit, a throttle valve in said induction conduit, means for supplying engine -operating fuel to said induction conduit, means for supplying enrichment fuel to said induction conduit during cold engine conditions including an enrichment port in communication with said induction conduit, fuel enrichment valve means for said port and being adjustable to control the enrichment fuel flow therethrough to said conduit, a fast idle cam, cam follower means for said cam, a throttle linkage connected with said throttle valve for controlling the latter and being engageable with said follower means to limit the extent of closing of said throttle `valve depending on the relative positions of said cam and follower means, actuating means cooperable with said cam for positioning the latter and also cooperable with said enrichment valve means to adjust the latter, temperature sensing means responsive to engine temperature cooperable with said actuating means to position said cam and to adjust said enrichment valve means to decrease the minimum throttle opening and the ow of enrichment fuel through said enrichment port with increasing temperature, said throttle linkage including an unloader lever engageable with said cam to position the latter at an unloader position upon shifting of said throttle linkage to a wide open throttle position, said cam being cooperable with said actuating means to close said enrichment valve means when said cam is at said unloader position, and means responsive to the pressure in said induction conduit and cooperable with said actuating and temperature responsive means to augment the latter in decreasing said minimum throttle opening and said ow of enrichment fuel with increasing temperature when said engine is running.

16. In an internal combustion engine, a chokeless carburetor having an air inlet induction conduit, a throttle valve in said induction conduit, means for supplying engine operating fuel to said induction conduit, means for supplying enrichment fuel to said induction conduit during cold engine conditions including an enrichment port in communication with said induction conduit, fuel enrichment valve means for said port and being adjustable to control the enrichment fuel flow therethrough to said conduit, said valve means including a stem projecting through said port in the direction toward the induction conduit side of said port and being movable in said direction to cause said valve means to restrict said port, said stem being movable in the opposite direction to cause said valve means to decrease the restrictlon at sald port,

actuating means having a portion engageable with said stern at the induction conduit side of said port to adjust said valve means, temperature sensing means responsive to engine temperature and cooperable with said actuating means to adjust said valve means to decrease the flow of said enrichment fuel through said port with increasing temperature, and means responsive to engine operation and cooperable with said actuating means to augment the effect of said temperature sensing means in decreasing said enrichment fuel flow with increasing temperature when said engine is running. f

17. In an internal combustion engine, a chokeless carburetor having air inlet induction conduit means, a pair of throttle valves in separate parallel parts of said conduit means, means for supplying engine operating fuel to said parallel parts, means for supplying enrichment fuel to vsaid conduit means during cold engine conditions including an enrichment port arranged between said parallel ports and opening into a chamber in communication with each of said parallel parts, fuel enrichment valve means for said port and being adjustable to control the ow of enrichment fuel therethrough intro said chamber, said valve means including a stem projecting through said port into said chamber and being movable in the direction into said chamber to cause said Valve means to restrict said port, `said stern being movable in the opposite direction to cause said valve means to decrease the restriction at said port, actuating means having a portion in said chamber engageable with said stem for adjusting the latter in the aforenamed directions, temperature sensing means responsive to engine temperature and cooperable with said actuating means to adjust said valve means to decrease said enrichment fuel flow through said port with increasing temperature, and means responsive to engine operation and cooperable with said actuating means to augment the effect of said temperature sensing means in decreasing said enrichment fuel ow with increasing temperature when said engine is running.

18, In an internal combustion engine, means for supplying operating fuel to said engine, duct means for supplying enrichment fuel to said engine, adjustable valve means associated with said duct means for controlling the enrichment fuel ow therein to said engine, said valve means including a cold starting metering port and a cold running metering port and being shftable to a cold starting position to `supply enrichment fuel to said engine through both of said metering ports, lmeans responsive to engine operating conditions and operatively connected with said adjustable valve means to shift the latter to a cold running position to close said cold starting port when said engine is running within a predetermined temperature range.

References Cited in the le of this patent UNITED STATES PATENTS 2,043,514 Mennesson June 9, 1936 2,428,377 Morris Oct. 7, 1947 2,752,132 Nye .Tune 26, 1956 2,754,094 Mennesson July 10, 1956 

